Raven. A homemade Atari-like computer

[agranlund]

Have you got links for more info on these two machines? Does either feature any kind of video output? Did you build either of these yourself?

No I haven't built any other computer than the 68000/68008 one I made that get me hooked.
Blitz has 8bit ISA slots so I imagine video comes out of that, but I don't know how far he got and if he had video output going or not.
If I remember correctly the other one was supposed to use some kind of off-the-shelf video IC.
But no, I can't vouch for how well either of these work or how finished they got but I think they are great achievements regardless.

There are tons and tons of really cool homemade stuff on the Retrobrew wiki and forums:
https://retrobrewcomputers.org/doku.php

[agranlund]

this computer is for me, and that basically made everything solve itself and go rather quickly

The SRAMs are the best example of selfish design, and I still stand by them as the correct choice even though they are not to most peoples liking.
I know of course that they are objectively way overpriced for what little they give. But to me, going that route gave a lot and for what they gave they were insanely cheap.

It's funny that if it's something I enjoy I can spend hours on it, but as soon as I don't I end up translating that time to money equivalent and if it's worth paying my way out of it to get to where I want to be or just ignore the whole thing all-together :)
Now, I did want to make the computer so ignoring the whole project was not on the table.


So the question became; how long would struggling with getting DRAM to work delay me from having fun, and if I'm going to be spending a lot of precious spare time having not-fun then how much money is that time actually worth (according to my employer) ?

In that twisted context, those SRAMs was an absolute bargain..
I could buy tons of them and still "save money" (*), and more importantly begin to have fun immediately.
(*) I know that's not how it works.. but still, it was cheap enough paying my way out of something I did not want to do, to get me quickly to what I want to do.

So yeah, I love those little suckers and I would use them again :)

[stephen_usher]

Indeed. SRAM solves a lot of the complexity problems. No need for RAS/CAS or refresh circuits, just simple address and data lines and let the chip architects take care of the rest.

[Oldskool]

We have lift off. Thanks for all the help finding the fault..

IMG_2828.jpeg

A tiny piece of loose solder was stuck between the legs.
This was resolved by a reflow with some flux and a tiny soldering iron.
Some pictures at my friend (the expert) from this afternoon:

All the experts stuff

IMG_2822.jpeg

Checking all the legs

IMG_2824.jpeg

He was also repairing this. Anyone can guess what kind of computer this is?

IMG_2823.jpeg

[agranlund]

We have lift off. Thanks for all the help finding the fault..

Nice!!

[agranlund]

Let me know if you need me to dial back write-timing to gfxcard ram..

I very unscientifically had it at a point where my particular ET4K stopped making artifacts in mono resolution..
If one don't care about mono it was possible to make it more aggressive without 8bit mode being effected.
Unsurprisingly, the Mach32 appears to care even less - that chip was designed for PCI speeds after all.

[Oldskool]

Hi,

Mono resulution works without any issues.
Nova driver (menu) crashes a loth when counting and then it freezes. Sometimes it works and I can select a resolution however they all seem to look like this:

IMG_2829.jpeg

Edit
Mono resolution also looks strange with Nova driver (the buildin one emutos is OK)

IMG_2830.jpeg

Could ofcourse be a driver issue but maybe the timing issue mentioned. Can also try the other et4k I have later in the afternoon/evening.

Edit 2

It crashes if you do anything under Nova. Loading stuff from the cf is also very unstable.. (always so also without Nova. For instance jam sometimes loads but very often crashes when loading).

So system does not seem stable yet. Already switched to another mem stick (but no difference). Other videocard does also not make a difference.

[agranlund]

Mono resulution works without any issues.
Nova driver (menu) crashes a loth when counting and then it freezes. Sometimes it works and I can select a resolution however they all seem to look like this:

Are you running in x1 cpu mode by any chance?

[Oldskool]

Yes mostly x1 but x2 gives similar results however I did not perform a lot of testing with x2.

[agranlund]

Yes mostly x1 but x2 gives similar results however I did not perform a lot of testing with x2.

x1 should be considered broken or at least unfinished. I haven't been using it much/at all myself so it hasn't been a priority but last I looked I did take note that CPU<->68150 comms will be iffy in that mode.

My screen with Nova looks exactly like your screenshots when I tried x1 instead of x2.